package com.peng.leetcode.dynamic;

/**
 * MinPathSum
 *
 * @author: lupeng6
 * @create: 2021/1/20 22:00
 */
public class MinPathSum {

    public static void main(String[] args) {
        int[][] grid = {{1, 3, 1}, {1, 5, 1}, {4, 2, 1}};
        System.out.println(new MinPathSum().minPathSum(grid));
    }

    public int minPathSum(int[][] grid) {
        if (grid == null || grid.length == 0) {
            return 0;
        }

        int rows = grid.length;
        int cols = grid[0].length;

        int[][] dp = new int[rows][cols];


        // init
        dp[0][0] = grid[0][0];
        for (int i = 1; i < rows; i++) {
            dp[i][0] = dp[i - 1][0] + grid[i][0];
        }

        for (int i = 1; i < cols; i++) {
            dp[0][i] = dp[0][i - 1] + grid[0][i];
        }

        for (int i = 1; i < rows; i++) {
            for (int j = 1; j < cols; j++) {
                dp[i][j] = Math.min(dp[i - 1][j] + grid[i][j], dp[i][j - 1] + grid[i][j]);
            }
        }
        return dp[rows - 1][cols - 1];
    }

}
